Synthesis of Well-Defined N-Heterocyclic Carbene (NHC) Complexes of Late Transition Metals

N-heterocyclic carbenes (NHCs) have emerged as appropriate replacements for phosphines to synthesized highly active metal complexes in homogeneous catalysis. The advantages of NHCs over phosphines include ease of handling, minimal toxicity and powerful electron donating properties. They bind transition metals with no need of back-donation and yield complexes with enhanced stability. The ability of NHCs to bind all metals from the periodic table, in low and high oxidation states, creates an unprecedented opportunity for the design of new complexes. This dissertation is dedicated to the synthesis of well-defined organosilver and organogold complexes bearing NHC ligands. In addition, two short chapters describe briefly the synthesis of NHC acetylacetonate palladium(II) complexes, and the use of NHC ruthenium(II) indenylidene complexes in ring opening metathesis polymerization reactions. New silver(I) and gold(I) halide mono-NHC complexes are synthesized, structurally characterized, and compared to other existing silver(I) and gold(I) complexes. The silver cation trends to form thermodynamically favored bis-NHC complexes and the success for the synthesis of kinetically favored silver(I) mono-NHC complexes is strongly dependant of the carbene, the solvent, and the silver salts used. In contrast, the synthesis of gold(I) mono-NHC complexes appears easier specially by transmetalation starting from silver(I) NHC complexes. The reactivity of both metals NHC complexes is directly related to the strength of the metal-carbene bond. The gold(I) cation firmly bound to the carbene, undergoes oxidative addition with halogens to afford gold(III) NHC complexes, or dehalogenation in presence of inorganic silver salts to afford cationic gold(I) mono-NHC complexes in coordinating solvent. The coordinating solvent can be replaced by a neutral or anionic group to yield gold(I) NHC complexes with unusual ligands such as olefins, pyridines, sugars. In contrast, the silver(I) cation is weakly bound to the carbene, and silver(I) NHCs decompose in presence of halogens or inorganic silver salts. In conclusion the synthesis of the NHC complexes emphasizes deeply the similarities and the differences between silver and gold chemistries. While NHCs ideally stabilize gold(I) and(III) complexes, phosphines appears to be a more promising alternative than NHCs for the chemistry of silver

Synthesis of Well-Defined N-Heterocyclic Carbene (NHC) Complexes of Late Transition Metals

N-heterocyclic carbenes (NHCs) have emerged as appropriate replacements for phosphines to synthesized highly active metal complexes in homogeneous catalysis. The advantages of NHCs over phosphines include ease of handling, minimal toxicity and powerful electron donating properties. They bind transition metals with no need of back-donation and yield complexes with enhanced stability. The ability of NHCs to bind all metals from the periodic table, in low and high oxidation states, creates an unprecedented opportunity for the design of new complexes. This dissertation is dedicated to the synthesis of well-defined organosilver and organogold complexes bearing NHC ligands. In addition, two short chapters describe briefly the synthesis of NHC acetylacetonate palladium(II) complexes, and the use of NHC ruthenium(II) indenylidene complexes in ring opening metathesis polymerization reactions. New silver(I) and gold(I) halide mono-NHC complexes are synthesized, structurally characterized, and compared to other existing silver(I) and gold(I) complexes. The silver cation trends to form thermodynamically favored bis-NHC complexes and the success for the synthesis of kinetically favored silver(I) mono-NHC complexes is strongly dependant of the carbene, the solvent, and the silver salts used. In contrast, the synthesis of gold(I) mono-NHC complexes appears easier specially by transmetalation starting from silver(I) NHC complexes. The reactivity of both metals NHC complexes is directly related to the strength of the metal-carbene bond. The gold(I) cation firmly bound to the carbene, undergoes oxidative addition with halogens to afford gold(III) NHC complexes, or dehalogenation in presence of inorganic silver salts to afford cationic gold(I) mono-NHC complexes in coordinating solvent. The coordinating solvent can be replaced by a neutral or anionic group to yield gold(I) NHC complexes with unusual ligands such as olefins, pyridines, sugars. In contrast, the silver(I) cation is weakly bound to the carbene, and silver(I) NHCs decompose in presence of halogens or inorganic silver salts. In conclusion the synthesis of the NHC complexes emphasizes deeply the similarities and the differences between silver and gold chemistries. While NHCs ideally stabilize gold(I) and(III) complexes, phosphines appears to be a more promising alternative than NHCs for the chemistry of silver

The Role of Footwear, Foot Orthosis and Training-Related Strategies in the Prevention of Bone Stress Injuries: A Systematic Review and Meta-Analysis

International Journal of Exercise Science 16(3): 721-743, 2023. Objective: To evaluate the effectiveness of footwear, foot orthoses and training-related strategies to prevent lower extremity bone stress injury (BSI). Design: Systematic review and meta-analysis. Data sources: Four bibliographic databases (from inception until November 2021): Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and CINAHL. Eligibility criteria: Randomised controlled trials (RCTs) that assessed the risk of developing a BSI when using particular footwear, foot orthoses or training-related strategies such as muscle strengthening, stretching, and mechanical loading exercises. Results: Eleven studies were included in this systematic review. When wearing foot orthoses, the risk ratio of developing a BSI on any lower extremity bone is 0.47 (95% CI 0.26 to 0.87; p = 0.02). When doing pre-exercise dynamic stretching, the risk ratio of suffering a tibial BSI is 1.06 (95% CI 0.67 to 1.68; p = 0.79). No meta-analyses could be performed for footwear or training-related strategies. The quality of evidence for all these results is low considering the high risk of bias in each study, the low number of studies and the low number of cases in each study. Conclusion: This systematic review reveals the lack of high-quality studies in BSI prevention. Based on studies at high risk of bias, foot orthoses could potentially help prevent BSIs in the military setting. It is still unknown whether footwear and training-related strategies have any benefits. It is crucial to further investigate potential BSI prevention strategies in women and athletes. Research is also needed to assess the influence of running shoes and loading management on BSI incidence

Musim Ikan Di Perairan Laut Jawa Kabupaten Jepara dan Prediksi Lokasi Fishing ground-nya

Sumberdaya ikan di Kabupaten Jepara cukup besar, namun hingga sekarang para nelayan menangkap ikan masih tradisional, hanya berdasarkan pengalaman tahun sebelumnya dan feeling semata.Variabilitas musim berpengaruh terhadap variabilitas kesuburan perairan baik secara temporal maupun spasial. Variabilitas kesuburan perairan selanjutnya berpengaruh terhadap waktu musim ikan dan lokasi fishing ground-nya. Pemahaman yang baik tentang waktu musim ikan dan lokasi fishing ground-nya akan membuat usaha penangkapan bisa lebih efektif, efisien waktu dan biaya serta hasilnya lebih optimal. Penelitian ini bertujuan mengkaji waktu musim ikan sekaligus masa pacekliknya di Perairan Laut Jawa Kabupaten Jepara dan membuat prediksi lokasi fishing ground-nya. Metode yang digunakan deskriptif berdasarkan pendekatan analisis data citra satelit, wawancara dengan kelompok nelayan dan survei lapangan. Berdasakan hasil penelitian menunjukkan waktu musim ikan di Perairan Kabupaten Jepara terjadi umumnya pada musim peralihan I (Maret-Mei) dan pada musim peralihan II (September-Nopember). Puncak musim ikan (panen ikan) umumnya pada bulan April atau Mei dan September atau Oktober. Masa Paceklik ikan di perairan Kabupaten Jepara tampak berkaitan dengan angin, ketika puncak angin terkuat (Desember-Januari) maka produktifitas penangkapan ikan menunjukkan nilai terendah (paceklik ikan). Lokasi fishing ground di perairan pesisir Jepara yang utama ada di tiga lokasi pertama di sekitar Pulau Mandalika, kedua yaitu di sekitar Pulau Panjang dan yang ketiga di Sebelah Barat Kecamatan Kedung. Lokasi fishing ground di wilayah perairan Kecamatan Karimunjawa yang utama ada di tiga lokasi pertama yaitu di sebelah barat Pulau Karumunjawa, kedua disebelah barat dan barat laut Pulau Parang dan ketiga yaitu di sebelah tenggara Pulau Nyamuk

Purification of androgen-binding protein from rat testis using high-performance liquid chromatography and physicochemical properties of the iodinated molecule

AbstractThe androgen-binding protein (ABP) has been purified 87 500-fold from rat testis using 4 steps of HPLC, with a yield of 14%. The molecule was 99% pure with a specific activity estimated to 16 600 pmol/mg protein. The iodinated molecule was eluted in 2 peaks in Sephacryl S300 gel filtration with a molecular mass estimated to be 92 600 ± 3300 and 50 300 ± 4000 Da. The column isoelectrofocusing of 125I-ABP demonstrated 3 isoproteins isoelectric at pH 4.7, 4.9 and 5.3 and the sedimentation coefficient was estimated to be 4.7 S in sucrose gradient ultracentrifugation. The 125I-ABP had similar physicochemical properties to the non-labelled ABP of epididymis

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation